The present invention relates to a sorter with an automatic removal apparatus which reads sorting information provided for documents such as postal matter to sort the documents and transfer them to corresponding stacking sections arranged in a plurality of stages in the vertical direction, and which automatically removes the documents at the stacking sections in unit stacks to convey them to the next step.
Various types of automatic postal matter processors are proposed in order to save labor involved in work related to mailing service. As an example, an automatic postal code number readout sorter is proposed which automatically reads the postal code numbers and automatically sorts the postal matter according to the readout postal code numbers. However, with such a conventional automatic postal code number readout sorter, the postal matter stacked at the stacking sections arranged in a plurality of stages in the vertical direction is taken out of the sections manually by the operator from one stacking section to another. The postal matter is then attached with an address card and are bound together. Therefore, one operator must always work with the sorter, and the operator must move within a wide range, exerting a big work load on the operator.
A prior art sorter is proposed in Japanese Utility Model Publication No. 52-22771. This publication proposes a removal conveying apparatus wherein the documents stacked at a feeding section are automatically removed to an outfeed section and the sides of the stacks of the documents at the outfeed sections are bound by brush-like holding members. According to this arrangement, the sliding of the stacked documents due to the vibrations or the like when the stacks of documents are fed out to the outfeed section or when they are conveyed. However, this publication does not describe a technique to feed out the stacks of documents from the outfeed section when the feed section is full of stacks of documents.
For this reason, a sorter with an automatic removal apparatus is desired which automatically removes the postal matter sorted into stacks and which sequentially feeds the stacks to an address card attaching unit and a binding unit.
The method for removing the postal matter from the stacking sections, by pushing the postal matter backward, that is, to the rear side of the sorter main body to place them on the conveyance path for conveying them to the next step, is suitable since a plurality of stacking sections are arranged in the horizontal direction. Furthermore, since the stacking sections are also arranged in a plurality of stages in the vertical direction, horizontal conveyance paths for conveying the postal matter removed from the stacking sections are also required in the corresponding number. In order to systematize the subsequent units such as the address card attaching unit and the binding unit and to effectively process the postal matter, it is preferable to join the postal matter conveyed by a plurality of horizontal convey paths.
For example, a method as shown in FIG. 1 has been recently proposed. Automatic push-out mechanisms (not shown) are arranged at respective stacking sections b, c and d of a sorter main body a. When the suitable number of pieces of postal matter is stacked, the stacks of postal matter A are pushed out backward and are placed on endless conveyer belts e, f and g arranged in correspondence with stacking sections b, c and d which are, in turn, arranged vertically at the rear side of the sorter main body a and which are arranged in a plurality of stages. The address cards are placed on the stacks of postal matter A after they are transferred to an elevator and a convey line (not shown).
However, with such a method, after the stacking sections are full of postal matter, and an empty tray is located at the corresponding location, the stack of postal matter is pushed out.
Therefore, the push-out operation is performed even if there is some postal matter on the convey path which is to be stacked at the stacking section involved in the push-out operation during the push-out time, or even if there is postal matter on the convey path which is to be rejected.